The invention relates to an assembly device for a circuit board and a lock body and relates to the technical field of circuit board assembly. The assembly device comprises a left side lock body installation support, a right side lock body installation support, a flat-mouth clamp and switch type magnetic seats. Different circuit boards can be installed by means of the coordination of opening-closing sizes of the flat-mouth clamp and the switch type magnetic seats, lock body components are fixed to corresponding grooves on the left side lock body installation support and the right side lock bodyinstallation support, then the fact that a fast card can be used to be the same as the loading card is realized. By means of the assembly device for the circuit board and the lock body, the problemsthat the manual one-by-one locating is needed in the installation of the lock body to the circuit board and the installation efficiency is low are well solved, the installation efficiency is improved,the production efficiency is drastically improved, and the production time and cost are saved.